Dental hydrocolloid syringe



- Aug. 7, 1945.A M. J. THOMPSON DENTAL HYDRocoLLoID sYnINGE' Filed Dec. 15, 1941 V ,MEV/ y Patented Aug. 7, 1945 Y IPwllllllzly'r' oFFlcE] 2,381,785 4linlv'rnl. HYDRoooLLoID SYRINGE Mrris'r Thompson, Los Angeles, Calif. fnpill'isationnesember 15, 1941,siia1No. 422,968 Y M 2vo1aims. (o1. 12s- 215) This invention relates to 7 denim hydro-consid syringes, andmoreparticularly tothe production of syringes adapted fori-the handling of dental hydrocolloids usedin the making of impressions.

` This application is a continuation-impart of f my application, SerialNo; 305,488,1-lled November 2l, l939,.for Method of andapparatusifor taking an impression of a cavity. for dental inlay.

In the'handling` of.dental yhydrocolloids itis necessary to have syringes which will enable' the dentistto utilize the-material in fluid condition and in such manner as to avoidxthe `separation of the materials composing .the hydrocolloids and `in such manner as to deliver the portions of. .the

hydrocolloidyto be' utilized to the pointswhere they arerequired at the requisite` fluidity to enable the hydrocolloid to reach all portions of the cavity. Particularly inthe making ofinlay impressions using such hydrocolloids it is. necessary. or

desirable to provide'asyringe which willenable vthe hydrocolloid to be injected` directly :intothe `cavity yirrespective of its position-within the mouth. i i `It isI therefore anA object of this invention. to provide a syringe in which the` hydrocolloid may be maintained at the desired fluidity and .against the possibility .of f contamination and which syringe has a rather ne discharge needle extending from its side permitting ejection of the hydrocolloid into cavities situated in the back part of the mouth arid next to the cheek.

Another object of this invention is to provide a syringe applicable for the handling of dental hydrocolloids which has a short discharge needle extending from its side whereby there is provided Va relatively short length of discharge passage enabling the hydrocolloid to be injected into the cavity in the required fluid condition.

Another object of this invention is to provide a syringe in which a hydrocolloid may be conditioned for use.

Another object'of this invention is to provide a dental hydrocolloid syringe which provides a means for the dispensing of small portions of hydrocolloid under the required condition of fluidity.

Other objects and advantages of this invention it is believed will be apparent from the following detailed description of a preferred embodiment thereof as illustrated in the accompanying drawing.

In the drawing: Figure 1 is a sectional elevation of a dental hy drocolloid syringe. embodying my invention illustrating as detached therefrom closing caps utiremaining portion of the plunger lized in the production of the syringe and for maintaining a definite huid-tight closure for the injection needle, the syringe being illustrated in broken length and ofl an enlarged size for the purpose of illustration.

Figure 2 is a sectional end View taken substantially on the line z -2 of Figure l, and enlarged to about twice thesize thereof.

In the embodiment of my invention as illustrated in the' accompanying drawing, the syringe is composed of a cylindrical barrel I which may be 'a section of a brass or other metal tube to which there is suitably secured a heat-retaining metal head 2. having a discharge passage 3 formed partially therethrough in the direction of the longitudinal axisof the tube I and an angled passage. 4 extending at an acute angle forwardly with relation to the axis o f the barrel I. The head 2` is frusto-conical with its sides substantially perpendicular to the passage 4. Mounted inthe passage 4 is a plug 6 threaded as indicated at I and carrying a ne injection needle 8.

The syringe structure as'thus formed is then covered with a rubber covering I0 which is molded `around the barrel I and head 2 below the thread v-'I as llimited by the position of the cap 9 forming on the-face 5 a closure seat II. There is also molded with the cover Ill a linger ange I2 spaced inward along the syringe from the open end thereof. A permanent closure cap I3 is provided which is threaded as indicated at I4 to permit the same being threaded upon the threads 1 of the plug 6. The cap I3 has the lowermost thread removed providing an annular closure flange I5 which seats upon the rubber seat I I maintaining a fluid-tight connection. As the cap I3 is screwed to the end of the threads l further screwing of the cap I3 down is arrested, thereby preventing destruction of the seat I I.

Mounted within the barrel I is a plunger I6 which may be of any suitableI or desirable con.- struction. As herein illustrated, the plunger I6 is formed with a core II threaded to receive a rod so that it may be suspended in a mold during which a rubber covering .2| is molded thereon, forming a head 2l] of larger diameter than the I6. The threaded end of the plunger is then filled with a screw I9. As the covering 2I is molded upon the plunger I6, thereis also molded thereon the actuating ange or head 24 which provides the means for gripping the plunger to enable the same to be moved in or out of the barrel I.

The syringe as thus formed provides a means within which the hydrocolloid may be heated to It will be apparent from the foregoing that the v injection passage formed by the passages 3 and 6 is relatively short and that as the h ead 2 is formed of heat-retaining metal it will retain for a greater period of time the heated condition required for maintaining the hydrocolloid at the temperature required for maintaining the necessary fluidity. The formation of the conical head 2 with the needle 8 extending at Substantially right angles from the side of the head enables me to project the needle beyond the end face 2a in such manner that the needle may be inserted into any cavity prepared for inlay.

The part ofv the passage which is exposed to the atmosphere out lof the syringe I as, for example, through the needle 8, is short so that little opportunity is permitted for lthe hydrocolloid to gel during injection. Projecting the needle 8 forward at an angle and from the side of the conical section, makes possible the introduction syringe is immersed in a container of heated water to bring the hydrocolloid contained therein to the desired fluidity.

The angle ofthe needle 8 as illustrated has been found particularly advantageous in reaching any inlay cavity in any tooth however any acute angle from the axis of the syringe may be employed with a lesser degree of efficiency. In reaching the back molars or wisdom teeth for such injections, it is advisable that the end of the needle 8 project near the forward end of the syringe in order to permit the injection to be made with a minimum of contact of the heated syringe with the interior of the mouth.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In a dental hydrocolloid syringe. the combination of a cylinder, a. plunger mounted to reciprocate in the cylinder, thel cylinder having a frusta-conical head mounted at one end, a passage formed through the' head, the passage having a section extending at substantially' right angled through the side `of the frusto-conical of the needle 8 into inlay cavities with a minimum Y of. interference.

The syringe embodying my invention as herein illustrated is primarily for the purpose of injecting hydrocolloids into cavities for thepurpose of making impressions for the production of inlays and provides also a dispensing instrument within which the -hydrocolloid is conditioned as to temperature and fluidity as set forth in my copending application, SerialNo. 305,488, hereinabove referred to. 'Y 1 a 'I The needle 8 has a fine discharge aperture therethrough preferably between the range of'a 10 andf25 vgauge needle, enabling the careful handling of the very small quantities. of hydrocolloid required.

As the syringe-forms the means within A'which the hydrocolloid is conditioned, it is essential that'the aperture formed through the needle 8 -be closed to prevent interchange of fluid as the head, and a relatively ne discharge needle mounted in and extending from thev discharge passage to a point in advance of the frusto-conical head.

2. In a dental hydrocolloid syringe, the combination of a cylinder formed of a tube and having a frusto-conical head secured to the discharge end of the tube, the passage formed through the head emitting in a direction substantially at right-angles to the side of the frusto-conical head, a discharge'xplug threaded in the discharge passage and having a fine needle discharge which extends to a point in advance of the frusto-conical head, a lcapI member adapted to be threaded to the plug, said cap member having its end threads removed whereby threading of the cap upon the plug to jam the threads is prevented, and the cylinder having a covering thereover, said coveringhaving an extended grip flange.

MORRIS J. THOMPSON. 

